on a slightly different note i was to ask a question but found this info myself concerning escape velocity:

Quote:

...launched with an initial velocity greater than Vesc, it will rise and never return. We must give the particle enough kinetic energy to overcome all of the negative gravitational potential energy. Thus, if m is the mass of the ball, M is the mass of the earth, and R is the radius of the earth, the potential energy is -GmM /R. The kinetic energy of the ball, when it is launched, is mv2/2. We thus have

so am i correct in my understanding that it is the escape velocity (from ground) one is talking about when one says that the escape velocity to get out of earths gravity is 40,320 kph?

edit: anyway if so it would be 11200 mps (same number but in mps (metric meters per second not miles)) for a rail gun system. some time would be needed to accelerate slowly if it were to carry humans (and extremely fine timing of the rail magnets as higher and higher speeds are attained).

Which improvements of rocket launches from balloons are provided by JP Aerospace's Tandems? For one and the same rocket to be launched they are of more mass because of the construction making them tandems - but the construction might have advantages for rocket launches.

And how about this: take the Dark Sky Station, but rather than mounting the tubes in a star shape, you connect them end-to-end into a torus. Hang the rocket underneath vertically in the middle, and launch through the hole. To lift a reasonably sized rocket the torus would have to be pretty big anyway, so the exhaust may not be a problem (haven't done any calculations though!) The main problem would probably be keeping the torus open. What would be the optimum shape to keep that from happening?

Humm, Interesting thread! Making a nice big balloon is possible with polyethylene and a hot weld tool. Hydrogen is cheaper. We could use some help guy's if your still interested in working on a balloon platform. Our platform must lift 2000 lbs. to @100k ft. You can get involved in our Near Space Expedition if you like. We are ready for a launch we just need a USB Sirf compatible GPS and some map calibrations, finish up our hydrogen generator. We could use the help.

I've been meaning to build an Airship for some time. The thing that is holding me back is finding somewhere that I can buy Mylar and Hydrogen from.

Nearspace itself offers possibilities for Tourism. A Nearspace hotel at 20km altitude would be cheaper than a space hotel, yet will have the same stunning views and gravity.

One possible spacecraft I've concieved is an Airship to Orbit SSTO, using electrically enhanced H2O2/Ethanol rockets. They could spike the Isp high enough for SSTO.

For the Torus idea, pressure would be enough if you overpressurised the envelope. Probably you'd want an inflated beam runniong round the inside to keep its shape. Since rocklets don't tend to launch straight up anyway, a drop launch would be easier.